The effectiveness of noninvasive positive pressure ventilation to enhance preoxygenation in morbidly obese patients: a randomized controlled study.
BACKGROUND
Noninvasive positive-pressure ventilation (NPPV) with pressure support-ventilation and positive end-expiratory pressure are effective in providing oxygenation during intubation in hypoxemic patients. We hypothesized administration of oxygen (O2) using NPPV would more rapidly increase the end-tidal O2 concentration (ETO2) than preoxygenation using spontaneous ventilation (SV) in morbidly obese patients.


METHODS
Twenty-eight morbidly obese patients were enrolled in this prospective randomized study. Administration of O2 for 5 min was performed either with SV group or with NPPV (pressure support = 8 cm H2O, positive end-expiratory pressure = 6 cm H2O) (NPPV group). ETO2 was measured using the anesthesia breathing circuit, and is expressed as a fraction of atmospheric concentration. The primary end-point was the number of patients with an ETo(2) >95% at the end of O2 administration. Secondary end-points included the time to reach the maximal ETO2 and the ETO2 at the conclusion of O2 administration.


RESULTS
A larger proportion of patients achieved a 95% ETO2 at 5 min with NPPV than SV (13/14 vs 7/14, P = 0.01). The time to reach the maximal ETO2 was significantly less in the NPPV than in the SV group (185 +/- 46 vs 222 +/- 42 s, P = 0.02). The mean ETO2 at the conclusion of O2 administration was larger in the NPPV group than the SV group (96.9 +/- 1.3 vs 94.1 +/- 2.0%, P < 0.001). A modest, although significant, increase in gastric distension was observed in the NPPV group. No adverse effects were observed in either group.


CONCLUSIONS
Administration of O2 via a facemask with NPPV in the operating room is safe, feasible, and efficient in morbidly obese patients. In this population NPPV provides a more rapid O2 administration, achieving a higher ETO2.
Delay
Jean-Marc
JM
Department of Anesthesia and Critical Care B (DAR B), Hôpital Saint Eloi, 80, avenue Augustin Fliche, 34295 Montpellier Cedex 5, France.
Sebbane
Mustapha
M
Jung
Boris
B
Nocca
David
D
Verzilli
Daniel
D
Pouzeratte
Yvan
Y
Kamel
Moez El
ME
Fabre
Jean-Michel
JM
Eledjam
Jean-Jacques
JJ
Jaber
Samir
S
D000328:Adult; D000764:Anesthesia, Closed-Circuit; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000379:methods*; D007385:Intermittent Positive-Pressure Ventilation / Q000379:methods*; D009767:Obesity, Morbid / Q000150:complications / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D018579:Patient Selection; D011175:Positive-Pressure Respiration / Q000379:methods*; D012121:Respiration, Artificial; D012131:Respiratory Insufficiency / Q000209:etiology / Q000628:therapy; D013990:Tidal Volume
D010100:Oxygen